018563   Li Z.S.;Liu D.L.;Yang X.Y.;Wu X.Q.;Tan Y.; Wang B.C. (School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China, Email: lizs@ustc.edu) : Geological and geochemical characteristics of source rocks of carbon dioxide in deep strata of Northern Songliao basin, northeast China. J Geol Soc India 2008, 71(2), 189-200.

Based on studies of major element, rare earth element, fluid inclusion and absorbed gas, the possible source matters of carbon dioxide (CO₂) and their potentialities to form gas accumulations in deep northern Songliao basin, NE China, were addressed in this paper. Mantle-derived magma, volcanic rocks, carbonate rocks and organic matters are four kinds of potential source matters, whose significances are degressive in turn and vertical distributions could be divided into shallow, middle, deep and deeper levels. In shallow level, the source matters of CO₂ are volcanic rocks and carbonation rocks with higher total carbon contents and absorbed CO₂ contents, 0.24%-7.76% and 0.213%-1.387% respectively. The absorbed CO₂ contents of volcanic rocks are negatively correlated with the SiO₂ contents, and positively with the Na₂O+K₂O contents. The principal source matters are metamorphic carbonate rocks in middle level and mantle-derived magma in deep and deeper levels. Higher CO₂ abundance in magmatic systems corresponding to deep volcanic rocks could be suggested by characteristics of lithogeochemistry and fluid inclusion as well as tectonic setting. The volcanic rocks of Yingcheng Formation and corresponding magmatic activities are the most favorable CO₂ source matters in northern Songliao Basin.

6 illus, 4 tables, 47 ref

018562   Lal N K;Siawal A;Kaul A K (NO, , 310, Lane 9, Mohit Nagar, Dehradun-248 001) : Evolution of east coast of India - a plate tectonic reconstruction. J Geol Soc India 2009, 73(2), 249-60.

The evolution of east coast of India is discussed within the ambit of clearly identifiable four major tectonic stages which had a profound effect in shaping the tectonic grain of the east coast basins. The evolutionary process began with rift related crustal extension between India and Sri Lanka as a consequence of Africa-Antarctica rifting and development of Natal Basin. An arm of this rift led to initial extension in the Cauvery Basin and failed. Later, the India-West Australia rift propagated further in southwesterly direction initiating Mahanadi and Krishna-Godavari Basins. This extension was an oblique one with Nayudupeta high acting as pivot. The oblique extension followed by asymmetric sea-floor spreading developed transpression along India-Sri Lanka and Antarctica junction, resulting in a NNW-SSE trending transcurrent fault along which Antarctica moved southward. Subsequently, entire east coast evolved through a more or less uniform post rift stage.

8 illus, 2 tables, 46 ref

018561   Kulkarni M A;Patil S;Rama G V;Sen P N (Atmospheric and Space Sciences Dep, Pune Univ, Pune-411 007, Email: makarand_kulkarni@hotmail.com) : Wind speed prediction using statistical regression and neural network. J Earth Syst Sci 2008, 117(4), 457-63.

Prediction of wind speed in the atmospheric boundary layer is important for wind energy assess-ment, satellite launching and aviation, etc. There are a few techniques available for wind speed prediction, which require a minimum number of input parameters. Four different statistical techniques, viz., curve fitting, Auto Regressive Integrated Moving Average Model (ARIMA), extrapolation with periodic function and Artificial Neural Networks (ANN) are employed to predict wind speed. These methods require wind speeds of previous hours as input. It has been found that wind speed can be predicted with a reasonable degree of accuracy using two methods, viz., extrapolation using periodic curve fitting and ANN and the other two methods are not very useful.

4 illus, 3 tables, 8 ref

018560   Krishnakumar K N;Prasad Rao G S L H V; Gopakumar C S (Agricultural Meteorology Dep, College of Horticulture, Kerala Agricultural Univ, Vellanikkara, Thrissur-680 656) : Climate change at selected locations in the Kerala state, India. J Agrometeorol 2008, 10(1), 59-64.

Rainfall and number of rainy days showed declining trend during the southwest monsoon (June-September) at four selected locations viz., Pilicode, Vellanikkara Amabalavayal and Pampadumpara across Kerala State, India with a maximum rate of 22.0 mm/year at Vellanikkara in the case of rainfall. Significant decline in rainfall from 2000 to 2005 was reflected in the above trend at Vellanikkara. Ambalavayal and Pampadumpara showed a rise in maximum temperature at the rate of 0.006°C/year and 0.04°C/year, respectively on annual basis. At Pampadumpara, the difference between maximum and minimum temperatures is likely to rise as maximum temperature was increasing while minimum temperature is declining. Cooler summers are expected at all the locations and may be significant at Vellanikkara (-0.05°C/year) due to pre - monsoon showers.

3 illus, 2 tables, 4 ref

018559   Krishna Moorthy K;Satheesh S K;Suresh Babu S; Dutt C B S (Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum-695 022) : Integrated campaign for aerosols, gases and radiation budget (ICARB). J Earth Syst Sci 2008, 117(S1), 243-62.

Presents an overview of the ICARB field experiment, the database generated, and some of its interesting outcomes though these are preliminary in nature. The ICARB has revealed significant spatio-temporal heterogeneity in most of the aerosol characteristics both over land and ocean. Observed aerosol loading and optical depths were comparable to or in certain regions, a little lower than those reported in some of the earlier campaigns for these regions. The preliminary results indicate: low (< 0.2) aerosol optical depths (AOD) over most part of the Arabian Sea, except two pockets; one off Mangalore and the other, less intense, in the central Arabian Sea at ~18°N latitude; High Angstrom exponent in the southern Arabian Sea signifying steep AOD spectra and higher abundance of accumulation mode particles in the southern Arabian Sea and off Mangalore: Remarkably low Angstrom exponents signifying increased concentration of coarse mode aerosols and high columnar abundance in the northern Arabian Sea; Altitude profiles from aircraft showed a steady BC level up to 3 km altitude with structures which were associated with inversions in the atmospheric boundary layer (ABL); A surprisingly large increase in the BC mass fraction with altitude; Presence of a convectively mixed layer extending up to about 1 km over the Arabian Sea and Bay of Bengal; A spatial off shore extent of < 100km for the anthropogenic impact at the coast; and Advection of aerosols, through airmass trajectories, from west Asia and NW arid regions of India leading to formation of elevated aerosol layers extending as far as 400 km off the east coast.

^iia14 illus, 4 tables, 65 ref

018558   Kotal S D;Roy Bhowmik S K;Kundu P K;Das A K (India Meteorological Dep, , New Delhi-110 003) : Statistical cyclone intensity prediction (SCIP) model for the Bay of Bengal. J Earth Syst Sci 2008, 117(2), 157-68.

A statistical model for predicting the intensity of tropical cyclones in the Bay of Bengal has been proposed. The model is developed applying multiple linear regression technique. The model parameters are determined from the database of 62 cyclones that developed over the Bay of Bengal during the period 1981-2000. The parameters selected as predictors are: initial storm intensity, intensity changes during past 12 hours, storm motion speed, initial storm latitude position, vertical wind shear averaged along the storm track, vorticity at 850 hPa, Divergence at 200 hPa and sea surface temperature (SST). When the model is tested with the dependent samples of 62 cyclones, the forecast skill of the model for forecasts up to 72 hours is found to be reasonably good. The average absolute errors (AAE) are less than 10 knots for forecasts up to 36 hours and maximum forecast error of order 14 knots occurs at 60 hours and 72 hours. When the model is tested with the independent samples of 15 cyclones (during 2000 to 2007), the AAE is found to be less than 13 knots (ranging from 5.1 to 12.5 knots) for forecast up to 72 hours. The model is found to be superior to the empirical model proposed by Roy Bhowmik et al (2007) for the Bay of Bengal.

6 illus, 6 tables, 16 ref

018557   Kedia S;Ramachandran S (Space and Atmospheric Sciences Div, Physical Research Laboratory, Ahmedabad-380 009, Email: sumita@prl.res.in) : Latitudinal and longitudinal variation in aerosol characteristics from sun photometer and MODIS over the Bay of Bengal and Arabian sea during ICARB. J Earth Syst Sci 2008, 117(S1), 375-87.

Spatial variations in aerosol optical properties as function of latitude and longitude are analysed over the Bay of Bengal and Arabian Sea during ICARB cruise period of March-May 2006 from in situ sun photometer and MODIS (Terra. Aqua) satellite measurements. Monthly mean 550 nm aerosol optical depths (AODs) over the Bay of Bengal and Arabian Sea show an increase from March to May both in spatial extent and magnitude. AODs are found to increase with latitude from 4°N to 20°N over the Bay of Bengal while over Arabian Sea, variations are not significant. Sun photometer and MODIS AODs agree well within ±1σvariation. Bay of Bengal AOD (0.28) is higher than the Arabian Sea (0.24) latitudinally. Aerosol fine mode fraction (FMF) is higher than 0.6 over Bay of Bengal, while FMF in the Arabian Sea is about 0.5. Bay of Bengal α(~ 1) is holier than the Arabian Sea value of 0.7, suggesting the dominance of fine mode aerosols over Bay of Bengal which is corroborated by higher FMF values over Bay of Bengal. Air back trajectory analyses suggest that aerosols from different source regions contribute differently to the optical characteristics over the Bay of Bengal and Arabian Sea.

6 illus, 1 table, 20 ref

018556   John B;Rajendran C P (NO, , Geological Survey of India, Lucknow-226 020, Email: b_johnp@yahoo.co.in) : Geomorphic Indicators of neotectonism from the precambrian terrain of Peninsular India: a study from the Bharathapuzha basin, Kerala. J Geol Soc India 2008, 71(6), 827-40.

Peninsular India is considered tectonically stable even though a few damaging earthquakes occurred here. Most of the causative faults are detected only after the occurrence of the earthquakes. The present study is an attempt to demarcate such active structures, from the Precambrian crystalline terrain of Peninsular India, through remote sensing, geomorphic analysis and field verification. The study area falls in the vicinity of Palghat Gap, a prominent physiographic break in the Western Ghats, where a low level seismicity is reported since 1989. The study identified a WNW-ESE regional structure, which has influenced the drainage network of the area. The right angled turn of Bharathapuzha River at Desamangalam near this structure shows the influence of the structure to the drainage system. This structure is also characterized by the presence of a waterfall and a brittle fault dated neotectonic activity. The drainage basins lying south of this structure show anomalous values of asymmetry factors (>65 or <35). The Transverse Topographic symmetry factors also show anomalous pattern on either end of this structure and display a consistent shift in drainages towards southwest in the southern block. It is further observed that the ratio of valley floor width to valley height is very low (<8) in the river segment flowing along the WNW-ESE structure where the river might have been influenced by the on going activity of the structure. The slope induced by the reverse movement of the structure/fault results in the adjustments of drainage network in the form of channel blocks or shifts leaving paleochannels. The present study suggests that the structure, defined by the abandoned river channels, geomorphic anomalies, local seismicity and a brittle fault, is an active fault and capable of producing moderate seismic events.

7 illus, 2 tables, 37 ref

018555   Jayananda M;Miyazaki T;Gireesh R V;Mahesha N; Kano T (Geology Dep, Bangalore Univ, Bangalore-560 056, Email: mjayananada@rediffmail.com) : Synplutonic mafic dykes from late Archaean granitoids in the Eastern Dharwar craton, Southern India. J Geol Soc India 2009, 73(1), 117-30.

Presents a first overview of the synplutonic mafic dykes (mafic injections) from the 2.56 - 2.52 Ga calc-alkaline to potassic plutons in the Eastern Dharwar Craton (EDC). The host plutons comprise voluminous intrusive facies (dark grey clinopyroxene-amphibole rich monzodiorite and quartz monzonite, pinkish grey porphyritic monzogranite and grey granodiorite) located in the central part of individual pluton, whilst subordinate anatectic facies (light grey and pink granite) confined to the periphery. The enclaves found in the plutons include highly angular screens of xenoliths of the basement, rounded to pillowed mafic magmatic enclaves (MME) and most spectacular synplutonic mafic dykes. The similar textures of MME and adjoining synplutonic mafic dykes together with their spatial association and occasional transition of MME to dismembered synplutonic mafic dykes imply a genetic link between them. The synplutonic dykes occur in varying dimension ranging from a few centimeter width upto 200 meters width and are generally dismembered or disrupted and rarely continuous. Necking of dyke along its length and back veining of more leucocratic variant of the host is common feature. They show lobate as well as sharp contacts with chilled margins suggesting their injection during different stages of crystallization of host plutons in magma chamber. Local interaction, mixing and mingling processes are documented in all the studied crustal corridors in the EDC. The observed mixing, mingling, partial hybridization, MME and emplacement of synplutonic mafic dykes can be explained by four stage processes: (1) Mafic magma injected during very early stage of crystallization of host felsic magma, mixing of mafic and felsic host magma results in hybridization with occasional MME; (2) Mafic magma introduced slightly later, the viscosities of two magmas may be different and permit only mingling where by each component retain their identity; (3) When mafic magma injected into crystallizing granitic host magma with significant crystal content, the mafic magma is channeled into early fractures and form dismembered synplutonic mafic dykes and (4) Mafic injections enter into largely crystallized (>80% crystals) granitic host results in continuous dykes with sharp contacts. The origin of mafic magmas may be related to development of fractures to mantle depth during crystallization of host magmas which results in the decompression melting of mantle source. The resultant hot mafic melts with low viscosity rise rapidly into the crystallizing host magma chamber where they interact depending upon the crystallinity and viscosity of the host. These hot mafic injections locally cause reversal of crystallization of the felsic host and induce melting and resultant melts in turn penetrate the crystallizing mafic body as back veining. Field chronology indicates injection of mafic magmas is synchronous with emplacement of anatectic melts and slightly predates the 2.5 Ga metamorphic event which affected the whole Archaean crust. The injection of mafic magmas into the crystallizing host plutons forms the terminal Archaean magmatic event and spatially associated with reworking and cratonization of Archaean crust in the EDC.

18 illus, 56 ref

018554   Javed A;Wani M H (Geology Dep, Aligarh Muslim Univ, Aligarh-202 002, Email: akram_javed@rediffmail.com) : Delineation of groundwater potential zones in Kakund wastershed, Eastern Rajasthan, using remote sensing and GIS techniques. J Geol Soc India 2009, 73(2), 229-36.

The remotely sensed data provides synoptic viewing and repetitive coverage for thematic mapping of natural resources. In the study hydrogeomorphological mapping has been carried out in Kakund watershed, Eastern Rajasthan for delineating groundwater potential zones. IRS-ID LISS III Geocoded FCC data in conjunction with Survey of India toposheet (1:50000 scale) and field inputs were used for thematic mapping. Geomorphic units identified through visual interpretation of FCC include: alluvial plain, plateau, valley fills, intermontane valleys, hurried pediment, residual hills, and linear ridges. In addition, lineaments were mapped since they act as conduit for groundwater recharge. Majority of the lineaments trends NE-SW and a few along NW-SE directions and are confined to the southern and southeastern parts of the watershed. Based on hydrogeomorphological, geological and lineament mapping the Kakund watershed has qualitatively been categorized into four groundwater potential zones, viz. good to very good, moderate to good, poor to moderate and very poor to poor. The study reveals that only 10.97% of the area has good to very good, 35.41 % area with moderate to good, 49.04 % of the area has poor to moderate, while remaining 4.57% has poor to very poor groundwater potential.

1 illus, 2 tables, 15 ref

018553   Janardhana Raju N;Prahland Ram;Dey S (Hydrogeology Div, Geology Dep, Banaras Hindu Univ, Varanasi-221 005, Email: rajunj7@yahoo.com) : Groundwater quality in the lower Varuna river basin, Varanasi district, Uttar Pradesh. J Geol Soc India 2009, 73(2), 178-92.

The lower Varuna River basin in Varanasi district situated in the central Ganga plain is a highly productive agricultural area, and is also one of the fast growing urban areas in India. The agricultural and urbanization activities have a lot of impact on the groundwater quality of the study area. The river basin is underlain by Quaternary alluvial sediments consisting of clay, silt, sand and gravel of various grades. The hydrogeochemical study was undertaken by randomly collecting 75 groundwater samples from dug wells and hand pumps covering the entire basin in order to understand the sources of dissolved ions, and to assess the chemical quality of the groundwater through analysis of major ions. Based on the total dissolved solids, two groundwater samples are considered unsuitable for drinking purpose, but all samples are useful for irrigation. Graphical treatment of major ion chemistry by Piper diagram helps in identifying hydro-geochemical facies of groundwaters and the dominant hydrochemical facies is Ca-Mg-HCO₃ with appreciable percentage of the water having mixed facies. As per Wilcox's diagram and US Salinity laboratory classification, most of the groundwater samples are suitable for irrigation except two samples (No's 30 and 68) which are unsuitable due to the presence of high salinity and medium sodium hazard. Irrigation waters classified based on residual sodium carbonate, have revealed that all groundwaters are in general safe for irrigation except one sample (No. 27), which needs treatment before use. Permeability index indicates that the groundwater samples are suitable for irrigation purpose. Although the general quality of groundwater of the lower Varuna River basin is suitable for irrigation purpose, fifty seven percent of the samples are found having nitrate content more than permissible limit (>45 mg/1) which is not good for human consumption. Application of N-Fertilizers on agricultural land as crop nutrients along the Varuna River course may be responsible for nitrate pollution in the groundwater due to leaching by applied irrigation water. The other potential sources of high nitrate concentration in extreme northern, southern and southwestern parts of study area are poor sewerage and drainage facilities, leakage of human excreta from very old septic tanks, and sanitary landfills. The high fluoride contamination (>1.5 mg/1) in some of the samples may be due to the dissolution of micaceous content in the alluvium. Nitrate and fluoride contamination of groundwater is a serious problem for its domestic use. Hence an immediate protective measure must be put into action in the study area.

5 illus, 3 tables, 50 ref

018552   Ivanov A V;Demonterova E I;Rasskazov S V; Yasnygina T A (NO, Institute of the Earth's Crust, Siberian Branch of Russian Academy of, Lermontov St. 128, Irkutsk 664 003, Russia, Email: aivanov@crust.irk.ru) : Low-Ti melts from the southeastern Siberian traps large igneous province: evidence for a water-rich mantle source?. J Earth Syst Sci 2008, 117(1), 1-21.

Siberian Traps Large Igneous Province (STLIP) is one of the most voluminous volcanic provinces on Earth. The dominant erupted rocks are low-Ti basalts, which make up 80% by volume of the classical Noril'sk lava sequence. In the west Siberian basin and Maymecha-Kotuy area, the low-Ti basalts make up about 99% and 50% by volume, respectively. Dolerite sills in the Angara- Taseevskaya Syncline at the southeastern STLIP exhibit trace element patterns and Sr isotope ratios typical of the low-Ti basalts of the Noril'sk sequence. The most Mg-rich (MgO 9.5-11 wt%) and hence least differentiated dolerites are characterized by trace element patterns with Ta-Nb depletion, low Ce/Pb and high Sr/Pr. These trace element features are similar to water-saturated, mantle wedge-derived island arc basalts. These imply an important role of subduction fluid-derived trace elements in the source of melting beneath the Angara-Taseevskaya Syncline and other regions of the STLIP. Less magnesium rocks (MgO 3.8-6.1wt%) with less prominent Ta-Nb depletion, higher Ce/Pb and lower Sr/Pr could be produced via olivine-plagioclase fractionation of primary high-magnesium melts.

10 illus, 2 tables, 114 ref

018551   Gupta S;Dandele P S;Verma M B;Maithani P B (Atomic Minerals Directorate for Exploration & Research, Atomic Energy, , Begumpet, Hyderabad-500 016) : Geochemical assessment of groundwater around Macherla-Karempudi area, Guntur district, Andhra Pradesh. J Geol Soc India 2009, 73(2), 202-12.

Groundwater in Palnad sub-basin is alkaline in nature and Na⁺ -Cl^-1 -HCO₃^- type around Macherla- Karempudi area in Guntur district, Andhra Pradesh. Total dissolved solids (TDS) show strong positive correlation with Cl^-, Na⁺, Ca²⁺ and Mg²⁺, and positive correlation with SO₄^2-, K⁺ and HCO₃^-. Calcareous Narji Formation is the dominant aquifer lithology, and water-rock interaction controls the groundwater chemistry of the area. Chloro-alkaline indices (CAI) are positive at Miriyala, Adigopula, Mutukuru, Macherla and Durgi suggesting replacement of Na⁺ and K⁺ ions from water by Mg⁺⁺ and Ca⁺⁺ ions from country rock through base exchange reactions. Negative CAI values are recorded at Terala, Rayavaram and Nehrunagar, which indicate exchange of Na⁺ and K⁺ from the rock as cation-anion exchange reaction (diloro-alkaline disequilibrium). TDS range from 91 to 7100 ppm (Avg. 835 ppm) and exceed the prescribed limit of drinking water around Mutukuru, Durgi, Rayavaram, Khambampadu and Ammanizamalmadaka areas. Scanty rainfall and insufficient groundwater recharge are the prime factors responsible for high salinity in the area. Fluoride content ranges from <1 to 3.8 ppm and contaminated areas were identified around Macherla (1 sq km; 3.8ppm), Mandadi (I sq km, 2. Ippm) and Adigopula (2 sq km, <1 to 3.7 ppm). The % Na⁺ content varies from 17 to 85 with the mean value of 57, and eighty (80) samples showed higher %Na⁺ in comparison to the prescribed limit of 60 for irrigation water. Sodium Adsorption Ratio (SAR) and % Na⁺ in relation to total salt concentration indicate that groundwater (51%) mostly falls under doubtful to poor quality for irrigation purpose. Groundwater of Adigopula village is fluoride contaminated and remedial measures are suggested to improve the water quality.

8 illus, 4 tables, 12 ref

018550   Gunnell Y;Harbor D (Geography Dep, , Paris-Diderot, CNRS UMR 8591, 2 Place Jussieu, 75205 Paris cedex 13, France, Email: gunnell@univ-paris-diderpt.fr) : Structural underprint and tectonic overprint in the angavo (Madagascar) and Western ghats (India) - implications for understanding scarp evolution at passive margins. J Geol Soc India 2008, 71(6), 763-79.

The land surfaces on either side of receding escarpments at continental passive margins are formed under the competing influence of drainage systems controlled by two separate base levels of erosion: proximal sea-levels in the coastal belt, and more distant and diverse base levels in upland river systems landward of the escarpment. Unequal erosion is therefore the engine that supports the asymmetric topography and persistence of local relief. A comparative study of the passive margin escarpments of western India and eastern Madagascar suggests that after a certain time has elapsed since initial continental breakup, steep landforms are either underpinned by resistant bedrock or recently formed by tectonics. Lithological controls, through which geological structure receives its topographic expression as the landscape erodes, are dominant. A morphostructural analysis of the Western Ghats escarpment in its Archaean section shows that its relief and morphology today are largely controlled by lithological heterogeneity and form a diverse gallery of homoclinal structures eroded out of the metamorphic and igneous fabric of the craton. Although in Madagascar late Cenozoic faulting locally affords an additional contribution to topographic expression, the growth and persistence of escarpment-supporting bedrock landforms is shown to be strongly pre-ordained by the pre-rift geological fabric. It also depends on the capacity of geomorphic agents in a particular climatic environment to reshape the landscape in response to drainage integration across the hinterland. It is argued that mature passive margin escarpments are essentially residual escarpments underpinned by a diverse assemblage of structurally controlled bedrock landforms.

7 illus, 70 ref

018549   Guha A;Vinod Kumar K;Kamaraju M V V;Basu Govindharaj K (Geosciences Div, National Remote Centre (Indian Space Research Organisation), Hyderabad-500 625, Email: arindam_g@nrsa.gov.in) : Potentials of alternate polarization of envisat ASAR data in geological mapping - a case study in Kurnool group of rocks, Andhra Pradesh. J Geol Soc India 2009, 73(2), 268-72.

The application of SAR data is a proven technology in geological studies but very few accounts are available in India, which can evaluate and demonstrate the utility of microwave signatures as an important tool for geological mapping. In this connection, the significance of polarization is an important parameter in enhancing geological elements. Present study reveals that the simple polarization composite prepared from different polarization channels can significantly aid the delineation of geological features as demonstrated from the Proterozok metasedimentary sequences of Kurnool Group. The polarization colour composites reveal that different sedimentary units can be differentiated on the basis of variable back scattering return in different polarization channel. Further geological structures of regional importance can also be delineated in these colour composite images. Comparative analysis of different composite images with published geological maps, illustrates the capabilities of the microwave polarization in enhancing geological elements and how they can be used in updating geological data.

4 illus, 6 ref

018548   Goswami B.;Bhattacharyya C. (NO, J.K. College, Puruliya-723 101, Email: bapigoswami69@yahoo.com) : Metamorphism of nepheline syenite gneisses from Chhotanagpur granite gneiss complex, Northeastern Puruliya district, eastern India. J Geol Soc India 2008, 71(2), 209-13.

Two contiguous, but spatially separated occurrences of nepheline syenites in the northeastern part of Puruliya district, one having biotite as the principal mafic component and the other having amphibole with subordinate biotite as mafic minerals are studied. Although modal mineralogy of nepheline syenites of these two bodies contrasts considerably, bulk chemical compositions of them remain almost same. Petrographic features give evidences of metamorphism. It is inferred that regional metamorphism of biotite-bearing nepheline syenite under granulite fades condition caused the appearance of amphibole-bearing nepheline syenite. During this metamorphic transition, possible reactions between minerals are also drawn.

2 illus, 2 tables, 13 ref

018547   Ghosh N;Chattopadhyay A (Geology Dep, Delhi Univ, Delhi-110 007) : Initiation and linkage of surface fractures above a buried strike-slip fault: an experimental approach. J Earth Syst Sci 2008, 117(1), 23-32.

In the study, two different series of riedel-type experiments were carried out with clay analogue models under different boundary conditions viz., (i) heterogeneous simple shear of the cover rocks above a buried strike slip fault (wrench system) and (ii) heterogeneous simple shear with a component of shear-normal compression of the overburden package above a basement fault (transpressional system), to observe the initiation and linkage of surface fractures with varying T' (where T' = thickness of the overburden normalized with respect to the width of the master fault). In the wrench system, Riedel shears were linked by principal displacement (Y) shears at early stages (shear strain of 0.8 to 1) in thin (2 < T' < 18) models and finally (at a minimum shear strain of 1.4) gave rise to a through-going fault parallel to the basement fault without development of any other fracture. Conjugate Riedel (R') shears develop only within the thicker (T' > 18) clay models at a minimum shear strain of 0.7. With increasing deformation (at a minimum shear strain of 1.2) two R' shears were joined by an R shear and finally opened up to make a sigmoidal vein with an asymmetry antithetic to the major fault-movement sense. Under transpression, the results were similar to that of heterogeneous simple shear for layers 2 < T' < 15. In layers of intermediate thickness (15 < T' < 25) early formed high angle R shears were cross cut by low angle R shears (at a minimum shear strain of 0.5 and shortening of 0.028) and "Riedel-within-Riedel" shears were formed within thick (T' > 25) models (at minimum shear strain of 0.7 and shortening of 0.1), with marked angularity of secondary fault zone with the master fault at depth.

16 illus, 26 ref

018546   Ghosh B;Praveen M N (NO, , Geological Survey of India, Operation: WB-SK-AN, Bhu Bijnan Bhawan, DK-6, Sector-II, Salt Lake, Kolkata-700 091, Email: bghosh_geol@hotmail.com ) : Indicator minerals as guides to base metal sulphide mineralisation in Betul belt, central India. J Earth Syst Sci 2008, 117(4), 521-36.

Zn-bearing minerals that act as indicator minerals for base metal sulphide mineralization from the Proterozoic Betul Belt, central India with special emphasis on their genetic significance have been discussed. Sulphide mineralisation is hosted by the felsic volcanic rocks and has similarities with volcanic-hosted massive sulphide deposits in other parts of the world. Synvolcanic hydrothermal alteration is crudely zoned with an inner high Mg-Ca core and an outer wider envelop of Al-Fe rich mineral assemblage. Most of the prospects have strata bound, moderately to steeply dipping, multiple, sub-parallel sheet like ore bodies composed of disseminated and semi-massive to massive ores. Zn-bearing spinel, staurolite, biotite and ilmenite typically occur within the foot-wall alteration zones in close proximity to the sulphide mineralization. Zincian spinel is ubiquitous irrespective of the nature of alteration zone. Zincian staurolite is nearly absent in Mg-Ca alteration zones but commonly present in Al-Fe alteration zone along with zincian ilmenite. Zn-bearing biotite in intimate association with zincian spinel is generally found in Mg-Ca alteration zone and in the transition to Al-Fe alteration zone. Most of these indicator minerals can be considered as products of desulphidation of sphalerite during metamorphism. Mechanisms other than desulphidation like formation of gahnite by overstepping of the zinc saturation limit of biotite during retrogression to chlorite and formation of zincian staurolite at the expense of gahnite is also recorded. Field presence of these minerals has immense significance in exploration in Betul Belt as they occur in close spatial relationship with the sulphide rich zones and therefore act as direct vectors to ore.

7 illus, 4 tables, 38 ref

018545   George S K;Nair P R (Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram-695 022, Email: prabha_nair@ussc.gov.in) : Aerosol mass loading over the marine environment of Arabian sea during ICARB: sea-salt and non-sea-salt components. J Earth Syst Sci 2008, 117(S1), 333-44.

Mass loading and chemical composition of atmospheric aerosols over the Arabian Sea during the pre-monsoon months of April and May have been studied as a part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB). These investigations show large spatial variabilities Aerosol mass loading as well as that of individual chemical species. The mass loading is 10 vary between 3.5 and 69.2μg m^-3, with higher loadings near the eastern and northern is of Arabian Sea, which decreases steadily to reach its minimum value in the mid Arabian Sea. The decrease in mass loading from the coast of India towards west is estimated to have a gradient of 1.53 μg m ^-3/° longitude and an e^-1 scale distance of ~2300 km. SO^2-₄, Cl^- arid Na⁺ found to be the major ionic species present. Apart from these, other dominating water-soluble components of aerosols are NO^-₃ (17%) and Ca²⁺ (6%). Over the marine environment of Arabian Sea, the non-sea-salt component dominates accounting to ~ 76% of the total aerosol mass. The spatial variations of the various ions are examined in the light, of prevailing meteorological conditions and airmass back trajectories.

12 illus, 1 table, 44 ref

018544   Ernest Raj P;Saha S K;Sonbawne S M;Deshpande S M;Devara P C S;Jaya Rao Y;Dani K K;Pandithurai G (NO, Indian Institute of Tropical Meterology, Pashan Road, Pune-411 008, Email: ernest@tropmet.res.in) : Lidar observation of aerosol stratification in the lower troposphere over Pune during pre-monsoon season of 2006. J Earth Syst Sci 2008, 117(S1), 293-302.

Lidar observations of aerosol vertical distributions in the lower troposphere along with observations of horizontal and vertical winds from collocated UHF radar (Wind Profiler) over a tropical Indian station, Pune during the pre-monsoon season (March-May) of 2006 as part of an ISRO-GBP national campaign (ICARB) have been examined. Lidar vertical profiles showed high aerosol concentrations in the surface layers and a subsequent gradual decrease with height. Results showed the presence of an elevated stratified aerosol layer around 2000-3500 m height which persisted throughout the months of March and April. Observed strong vertical gradients in both horizontal arid vertical winds in the lower troposphere seem to be a possible cause for the formation of elevated aerosol layers. Further, high daytime temperatures accompanied by dry conditions at the surface help to enhance the aerosol loading in the lower layers over this location.

9 illus, 22 ref

018543   Dumka U C;Krishna Moorthy K;Pant P;Hegde P; Sagar R;Pandey K (NO, Aryabhatta Research Institute of Observational Sciences, Nainital, Email: dumka@aries.ernet.in) : Physical and optical characteristics of atmospheric aerosols during ICARB at Manora peak, Nainital: a sparsely inhabited, high-altituted location in the Himalayas. J Earth Syst Sci 2008, 117(S1), 399-405.

Collocated measurements of the optical and physical properties of columnar and near-surface aerosols were carried out from Manora Peak, Nainital (a sparsely inhabited, high altitude location, ~2 km above mean sea level, in the Himalayas), during the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) under the Geosphere Biosphere Programme of the Indian Space Research Organization (ISRO-GBP). Under this, observational data of spectral aerosol optical depths (AOD), mass concentration of aerosol black carbon (M_B), mass concentration (M_T) and number concentration (N_t) of composite (total) aerosols near the surface and meteorological parameters were collected during the period February 15 to April 30, 2006. Though very low (<0.1 at 500 nm) AODs were observed during clear days, as much as a fourfold increase was seen on hazy days. The Angstrom exponent (a), deduced from the spectral AODs, revealed high values during clear days, while on hazy days a was low; with an overall mean value of 0.69 ± 0.06 for the campaign period. BC mass concentration varied between 0.36 and 2.87 μg m^-3 and contributed in the range 0.7 to 1.8% to the total aerosol mass. Total aerosol number concentration and BC mass concentration showed diurnal variation with a midnight and early morning minimum and a late afternoon maximum; a pattern quite opposite to that seen in low altitude stations. These are attributed to the dynamics of the atmospheric boundary layer.

7 illus, 2 tables, 24 ref

018542   Devaraju T C;Viljoen R P;Sawkar R H;Sudhakara T L (NO, , Rajamangala, Haliyal Road, Saptapur, Dharwad-580 001, Email: tcdevaraju@gmail.com) : Mafic and ultramafic magmatism and associated mineralization in the Dharwar craton, Southern India. J Geol Soc India 2009, 73(1), 73-100.

Evidence of mafic and ultramafic magmatism exists in many parts of the Dharwar craton which is divided into two blocks, the West Dharwar Craton (WDC) and the East Dharwar Craton (EDC). The mafic-ultramafic rocks occur in supracrustal/greenstone belts and in numerous enclaves and slivers in the WDC. The oldest recorded mafic-ultramafic rocks, which are mainly komatiitic in nature, are preserved in the Sargur Group which is more than 3.3-3.4 Ga old, the youngest being manifested by 63-76 Ma old mafic dyke magmatism, possibly related to Deccan volcanism. In the Sargur Group, ultramafics rocks greatly dominate over mafic lithological units. Both extrusive and intrusive varieties, the latter in the form of differentiated layered complexes, occur. Mafic volcanics exists in all the greenstone belts of the eastern block and in the Bababudan and Western Ghats belts of the western block. In addition to the Sargur Group where stratigraphic sequences are unclear, mafic magmatism is recorded in three different formations of the Bababudan Group and two sub-divisions of the Shimoga and Chitradurga Groups where basaltic flows are conspicuous. In the well studied greenstone belts of Kolar and Hutti in the EDC, three to four different Formations of mafic volcanic rocks have been mapped. Isotopic dating has indicated that while mafic magmatism in the greenstone belts of the EDC covers only a short time span of between 2.65 to 2.75 Ga, those in the Dharwar Supergroup of the WDC cover a much longer time span from 3.35 to 2.5 Ga. Mafic dyke magmatism has taken place repeatedly from 2.45 Ga to about 1.0 Ga, but, the peak of emplacement was between 1.8 and 1.4 Ga when the densely developed swarms on the western and south western portions of the Cuddapah Basin and in the Central part of Karnataka, were intruded. Emplacement of potassic ultramafic magma in the form of kimberlite-lamproite which is confined to the EDC, is a later magmatic event that took place between 1.4 Ga and 0.8 Ga. From a mineralization perspective, mafic magmatism of the supracrustal groups of the WDC and the greenstone belts of the EDC are the most important. V-Ti- magnetite bands constitute the most common deposit type recorded in the mafic-ultramafic complexes of the Sargur Group with commercially exploitable chromite deposits occurring in a number of belts. PGE mineralization of possible commercial value has so far been recorded in a single mafic-ultramafic complex, while copper-nickel mineralization occurs at certain localities in the Sargur and Chitradurga Groups. Cold mineralization hosted by mafic (occasionally ultramafic) rocks has been noted in many of the old workings located in supracrustal groups of rocks in the WDC and in the greenstone belts of EDC. Economically exploitable mineralization, however, occurs mainly in the greenstone belts of the Kolar, Ramagiri-Penkacherla and Hutti-Maski and along the eastern margin of the Chitradurga belt, where it is associated with a major N-S striking thrust zone separating the WDC from the EDC. Gold deposits of the eastern greenstone belts are comparable to those of the younger greenstone belts of Canada, Zimbabwe and Australia where the mineralization is associated with quartz carbonate veins often in iron-rich metabasic rocks. The gold was emplaced as hydrothermal fluids, derived from early komatiitic and tholeiitic magmas, and injected into suitable dilatent structures. The other common type of mineralization associated with the ultramafic rocks of the Sargur Group and supracrustal belts, particularly of the WDC, are asbestos and soapstone, related to autometamorphism/metasomatism. Ruby/sapphire deposits occur in places at the contacts of ultramafic rocks with the Peninsular Gneiss, and are related to contact metamorphism and metasomatism. Mineable magnesite deposits related to low-temperature hydrothermal/lateritic alteration exist in the zone of weathering, particularly in the more oli vine-rich rocks. Recent spurt in diamond exploration is offering promise of discovering economically workable diamondiferous kimberlite/lamproite intrusions in the EDC.

12 illus, 4 tables, 100 ref

018541   Deswal S (Civil Engineering Dep, National Institute of Technology, Kurukshetra-136 119, Email: deswal.leo@gmail.com ) : Modeling of evaporation using M5 model tree algorithm. J Agrometeorol 2008, 10(1), 33-8.

Investigates the prediction of pan evaporation using M5 Model Tree technique, evaluated for its applicability for predicting evaporation from meteorological data. Different combinations of input data were considered and the resulting values of evaporation were analysed and compared with those of existing techniques. The results suggest that the M5 Model could be successfully employed in estimating the evaporation from the available meteorological data set, within a scatter of ±15%, using the combination of air temperature, wind speed, sunshine hours and relative humidity) using M5 Model Tree algorithm. This study suggests the usefulness of M5 Model Tree technique with all the meteorological parameters considered together in predicting the pan evaporation from reservoirs.

2 illus, 2 tables, 14 ref

018540   Deka R L;Nath K K (Agrometeorology Dep, Assam Agricultural Univ, Jorhat-785 013) : Variability of climatic elements at Jorhat. J Agrometeorol 2008, 10(1), 89-92.

Major climatic elements of Jorhat, Assam for the period 1991-2000 have been compared with those of normal values. The total rainfall was lower than their normal values in all months except in February, September and October with significant decrease in the month of April. Pre-monsoon and monsoon rainfall decreased by 18.8 and 3.3 per cent, respectively. Monthly minimum temperature increased in all months with significant increase during June to September and in November. Monthly maximum temperature increased during April, July and from September to December but decreased during the remaining six months. The monthly temperature range was reduced. Seasonal minimum and seasonal average temperature also increased but seasonal maximum temperature slightly decreased except during post-monsoon season. Morning vapour pressure increased from May to September and decreased during the other months. Evening vapour pressure increased throughout the year. The increase in vapour content indicates intensification of Green House effect. Monthly evaporation also decreased significantly throughout the year. Decrease in bright sunshine hours was observed during January to June and August to October.

3 tables, 11 ref

018539   Chowdhury I;Dasgupta S P (Civil and Structural Engineering, , Petrofac International Limited, Sharjah, U.A.E., Email: Indrajit.Chowdary@petrofac.ae) : Dynamic analysis of piles under lateral loading. Indian Geotech J 2008, 38(3), 249-77.

An approach has been outlined where the dynamic pile stiffness and damping may be computed for piles under lateral loading. Both long and short piles have been considered in the analysis. The inertial effect of the pile has been incorporated in the analysis. The solution takes into account for the variation of shear modulus with depth and also the effect of partial embedment of the pile. Wherever possible, the results have been compared with the existing solutions and presented graphically.

7 illus, 6 tables, 24 ref

018538   Chatterjee N;Bhattacharji S (Earth Dep, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Room 54-1216, Cambridge, Massachusetts 02139, USA) : Trace element variations in deccan basalts: roles of mantle melting, fractional crystallization and crustal assimilation. J Geol Soc India 2008, 71(2), 171-88.

The variation in incompatible trace element contents of lower basaltic dykes and flows from different parts of the Deccan province was assessed through modelling of partial melting of primitive mantle and fractional crystallization of the parental melts coupled with crustal assimilation (AFC). Variations in Ba/Zr, Rb/Y and Nb/Y can be attributed to different degrees of partial melting of mantle. Variations in Zr, rare earth elements and Rb/Nb indicate fractional crystallization and significant coupled crustal assimilation away from the Deccan plume center. The Zr variation near the plume center can be explained through only fractional crystallization without the involvement of crust. AFC modelling of available Sr-Nd isotope data requires very high and unreasonable amounts of crustal assimilant implying that the parental magmas may have acquired their isotopic characteristics before AFC occurred in crustal magma chambers. The occurrence of AFC away from the plume center in the Narmada-Tapti rift region may be related to longer and greater magma-wall rock interaction in shallow crustal magma chambers due to crustal extension-related enlargement of the magma chambers, recharge with fresh, hot magma and convective mixing.

7 illus, 1 table, 71 ref

018537   Chakraborty C;Ghosh S K (Geological Studies Unit, Indian Statistical Institute, 203 B.T. Road, Kolkata-700 108, Email: chandan@isical.ac.in) : Pattern of sedimentation during the late paleozoic, Gondwanaland glaciation: an example from the Talchir formation, Satpura Gondwana basin, Central India. J Earth Syst Sci 2008, 117(4), 499-519.

23 illus, 51 ref

018536   Cem Koc A (Civil Engineering Dep, Pamukkale Univ, Kinikli Kampusu, 20017 Denizli, Turkey) : Evaluation of karstic aquifers contribution to streams by the statistical analysis of recession curves. J Earth Syst Sci 2008, 117(1), 59-67.

The extent of karstic aquifer contributions to a stream will be investigated by the statistical analysis of recession coefficients of recession curves. Six stream gauging stations on different streams in the western Mediterranean region of Turkey are selected. Recession periods of the streams are simulated by exponential and quadratic recession curve models. Recession coefficient series of the stream gauging stations are statistically investigated. The comparison of various statistical parameters shows that the recession coefficient series are fairly related to the karstic aquifer contributions. Especially, the measure of spread parameters, standard deviation and interquartile range of recession coefficient series are related to the extent of the karstic aquifer contributions to streams.

4 illus, 4 tables, 18 ref

018535   Bose M K (Geology Dep, Presidency College, 86/1 College Street, Kolkata-700 073) : Precambrian mafic magmatism in the Singbhum craton, Eastern India. J Geol Soc India 2009, 73(1), 13-35.

The Singhbhum craton has a chequred history of mafic magmatism spanning from early Archaean to Proterozoic. However, lack of adequate isotopic age data put constraints on accurately establishing the history of spatial growth of the craton in which mafic magmatism played a very significant role. Mafic magmatism in the craton spreads from ca.3.3 Ga (oldest "enclaves" of orthoamphibolites) to about 0.1 Ga ('Newer dolerite' dyke swarms). Nearly contemporaneous amphibolite and intimately associated tonalitic orthogneiss may represent Archaean bimodal magmatism. The metabasic enclaves are appreciably enriched and do not fulfill the geochemical characteristics of worldwide known early Archaean (>3.0 Ga) mafic magmatism. The enclaves reveal compositional spectrum from siliceous high-magnesian basalt (SHMB) to andesite. However, the occurrence of minor depleted boninitic type within the assemblage has so far been overlooked. High magnesian basalt with boninitic character of Mesoarchaean age is also reported in association with supracrustals from southern fringe of the granitoid cratonic nucleus. The subcontinental lithospheric mantle (SCLM) below the craton is conjectured to have initiated during the early Archaean. Significantly, recurrence of depleted magma types in the craton is observed during the whole span of mafic igneous activity which has been vaguely related to "mantle heterogeneity", although the alternative model of sequential mantle melting is also being explored. The Singhbhum craton includes the Banded Iron Formation (BIF) associated mafic lavas, MORB-like basic and komatiitic ultrabasic bimodal volcanism - documented as Dalma volcanics, Dhanjori lavas, and the Proterozoic Newer dolerile dykes. Three different types of REE fractionation patterns are observed in the BIP-associated mafic lavas. These are the REE unfractionated type is more depleted than N-MORB and some lavas with boninitic type of REE distribution. MORB-like basic and komatiitic ultrabasic (Dalma volcanics) are emplaced within the Proterozoic Singhbhum Basin (PSB). The vista of magmatism in the basin was controlled by a miniature spreading centre represented by the mid-basinal Dalma volcanic ridge. The volcano-sedimentary basinal domain of Dhanjori emerged at the interface of two subprovinces (viz. the mobile volcano-sedimentary belt of PSB and rigid granite platform) under unique stress environment related to extensional tectonic regime. Trace element distribution in Dhanjori lavas is remarkably similar to that in PSB minor intrusions and lavas (except a Ta spike in the latter). The Proterozoic Newer dolerite dykes within Singhbhum nucleus manifest an unusually wide spam of intrusive activity (ca 2100 Ma to 1100 Ma) and unexpectedly uniform mantle melting behaviour.

12 illus, 95 ref

018534   Bhattacharya D;Roy M;Dhirendra Kumar;Mishra P (Atomic minerals directorate for Exploration and Research, NR, New Delhi-110 066, Email: de-bhat@rediffmail.com) : Carbonate rock with igneous affinity from jungel valley, Sonbhadra district, Uttar Pradesh, Central India. J Geol Soc India 2008, 71(6), 808-14.

The Lower Proterozoic (1800-2400 Ma) Jungel Valley mafic-ultramafic complex (JVMUC) is an integral part of Mahakoshal greenstone belt in district Sonbhadra. The complex is known for its diversity of rocks like alkali olivine basalt, kimberlite and ultramafic lamprophyre. In addition to these, a carbonate rich rock having igneous affinity is being reported for the first time from this complex. High CaO, CO₂, Sr and Ce with low SiO₂, A1₂O₃ and TiO₂ characterise this rock. However, these rocks are not significantly enriched in incompatible elements and REE, implying that these may have possibly formed by partial melting of a depleted mantle at shallow depth. The geochemical characters combined with association of mantle derived rocks, presence of high level of carbonate in the lamprophyre and absence of sedimentary limestone in the area point towards an igneous origin, probably as a residual concentrate of a differentiated kimberlite-ultramafic lamprophyre sequence. Sr isotope data, which fall well within the range of reported carbonatites of India, suggest moderate crustal contamination. The mafic-ultramafic suite together with the carbonate rocks developed in Son-Narmada rift zone are interpreted to be coeval with the intrusive syenite pluton, alkali gabbro and lamprophyres of the adjoining areas and is related to the development of Mahakoshal greenstone belt.

3 illus, 1 table, 30 ref

018533   Bhakar S R;Singh R V;Chhajed N;Bansal A K (SWE Dep, CTAE, Udaipur-313 001, Email: srbhakar@rediffmail.com) : Stochastic modelling of relative humidity at Banswara. J Agrometeorol 2008, 10(1), 53-8.

Study was conducted to develop stochastic model for monthly minimum and maximum relative humidity using 12 years (1992-2003) data of Banswara. The performed statistical test indicates that the series of monthly minimum and maximum relative humidity data are trend free. Their periodic components can be presented satisfactorily by the second harmonics. The stochastic components of both monthly minimum and maximum relative humidity follow second order Markov model. Validation of generated was made with measured series. A high correlation coefficient of 0.9980 and 0.9976 for mean monthly minimum and maximum relative humidity respectively was observed. The correlation was tested by t-test and found to be highly significant at 1 per cent level. The standard error is quite low. The regression equation was very close to 1:1 line. Therefore, the developed model could be used for future prediction of mean monthly minimum and maximum relative humidity, at Banswara.

5 illus, 1 table, 9 ref

018532   Bhakar S R;Singh R V (Soil and Water Engineering Dep, College of Technology and Engineering, MPUAT, Udaipur-313 001, Email: srbhakar@redifmail.com) : Forecasting monthly wind speed for Udaipur region. J Agrometeorol 2008, 10(1), 46-52.

Stochastic modelling for mean monthly wind speed of Udaipur (Rajasthan) was done using 26 years (1978-2003) data. The performed statistical tests indicated that the series of the monthly wind speed data is trend free. The periodic component can be represented by third harmonic expression. The stochastic components of the mean monthly wind speed follow fourth order Markov model. The correlation coefficient between generated and measured mean monthly wind speed series was 0.9995 and found to be highly significant 1 per cent level. The standard error (5.57 mm) is quite low. The regression equation is very near to 1:1 line. Therefore, developed model can be used for future prediction of monthly wind speed at Udaipur.

5 illus, 1 table, 2 ref

018531   Bhakar S R;Iqbal M;Devanda M;Chhajed N;Bansal A K (Soil and Water Engineering Dep, College of Technology and Engineering, MPUAT, Udaipur-313 001) : Probablity analysis of rainfall at Kota. Indian J agric Res 2008, 42(3), 201-6.

Detailed statistical analysis of weekly and monthly rainfall for Kota was carried out using 35 years (1970-2004) daily rainfall data collected from Central Soil and Water Conservation Research Centre, Kota. The variation in weekly and monthly rainfall pattern was found to be more consistent during monsoon season. For forecasting the weekly and monthly rainfall Weibull's method, Normal, Log-normal and Gamma probability distribution functions were fitted. Calculated Chi-square values were compared with tabular values at 5 per cent level of significance. Using Weibull's (extreme value type III) method weekly rainfall was predicted at various probability levels. Gumbel distribution was found to be fitted well for prediction of weekly and monthly maximum rainfall.

2 illus, 2 tables, 6 ref

018530   Bhadra B K;Gupta A K;Sharma J R (Regional Remote Sensing Service Centre, Space Dep, , Cazri campus, Jodhpur-342 003, Email: bhadrabk@yahoo.com) : Saraswati nadi in Haryana and its linkage with the vedic Saraswati river - integrated study based on satellite images and ground based information. J Geol Soc India 2009, 73(2), 273-88.

Detailed studies on the status of Saraswati Nadi of northern Haryana have been carried out using multi date and multi resolution satellite images, GIS techniques and ground data. Palaeochannels have been delineated using remote sensing techniques and validated using discovered archaeological sites, sedimentological data from drilled wells and water quality data. Detailed analysis of hydrological data (rainfall and stream discharge), catchment area and petrographic analysis of rock samples have been done to decipher the dwindling state of Saraswati Nadi. Likelihood of Adi Badri as the place of origin of Saraswati Nadi and its possible linkage with the Vedic Saraswati River is discussed. Suggestions have been given for safeguarding and revival of Saraswati Nadi as a national heritage.

13 illus, 24 ref

018529   Bazargani-Guilani K;Rabbani M S (Geology Dep, Tehran Univ, Tehran-14155-6455, Iran, Email: kbazargani@ut.ac.ir) : Chemical composition and genesis of analcime from tuffs of karaj formation (Eocene), central alborz, Iran. J Geol Soc India 2008, 71(6), 859-67.

Analcime and other associated minerals occur in tuffs of Karaj and Kond Formations of Eocene age in Cheheltan Mountain in central Alborz, Iran. Details of field occurrence, petrography and geochemical studies of the analcimes are presented in this paper. The unit cell formula of analcime of the region is Na_9.9Al_13.0Si_35.0O₉₆. 14.0 H₂O. Analcime was found with quartz in the lower layers, with clinoptilolite and halite in middle layers and with calcite and dolomite in celestine bearing samples of low-K tuffs. The suitable conditions were available to form analcime without any zeolitic precursors in the samples of high K/Na ratio. The absence of high silicon zeolites, as precursors, in the samples of high K/Na ratio was attributed to the very high pH conditions. It is likely that the zeolitic precursors were necessary for formation of analcime in alkaline conditions of not very high pHs. The absence of pumpellyite in association with analcime, the relatively low thickness of the Karaj Formation in the study region and other analytical evidences are in favor of diagenetic character of the analcime in the east central Alborz.

5 illus, 2 tables, 31 ref

018528   Bandopadhyay P C;Chakrabarti U;Roy A (NO, , Geological Survey of India, Eastern Region, Salt Lake City, DK-6, Kolkata-700 091, Email: hiyabando@yahoo.co.uk) : First repost of trace fossils from palaeogene succession (Namunagarh Grit) of Andaman and Nicobar islands. J Geol Soc India 2009, 73(2), 261-7.

The Namunagarh grit of Eocene age in South Andaman island is a submarine fan deposit where sedimentation occurred in deep marine environment mainly by turbidity currents. The mudstone and fine-grained sandstone of the turbidite sequence yielded three ichnogenera viz. Thalassinoid.es, Teichichnus and Lorenzinia. Typically shallow marine Thalassinoides burrows co-occur with deep water burrows represented by Teichichnus wALorenzinia, indicating a dominant control of substrate, availability of food and rate of sedimentation against bathymetry on distribution of trace fossils. Trace fossils are particularly abundant in the mudstones pointing to a strong lithofacies control. A well-oxygenated muddy bottom with a low rate of sedimentation is envisaged. An order in the succession of traces could be deciphered. Simply constructed burrows of Thalassinoides appeared initially followed by complex structures of Teichichnus and ornate Lorenzinia.

3 illus, 1 table, 32 ref

018527   Bandopadhyay P C;Chakrabarti U;Mohapatra N R; Roy A (NO, , Geological Survey of India, Eastern Ragion, DK-6, Salt Lake City, Kolkata-700 091, Email: hiyabando@yahoo.co.uk) : New field evidence of coseismic coastal uplift during the December 2004 earthquake, North Andaman Island. J Geol Soc India 2008, 71(6), 871-4.

Reports documents ground uplift of a part of the eastern coast of North Andaman Island during the December 2004 earthquake. Emergence of a part of fringing coral reef above the high tide level has been recorded from the Kalipur beach. The newly emergent part of the coral reef is -75 m long, ~25 m wide and trends ESE paralleling the trend of the shore line. The study records appearance of a -600 m long and 200 m wide tombolo joining the Smith Island to the Ross Island off the eastern coast of North Andaman Island. Before the December 2004 earthquake it was a sand bar that emerged only during the low tides. Vertical movement of 0.4 m is calculated for the Kalipur beach while that between the Smith and Ross Islands is 0.7-0.8 m.

5 illus, 11 ref

018526   Bal S K;Choudhury B U;Sood A;Jalota S K;Singh H (Agrometeorology Dep, Punjab Agricultural Univ, Ludhiana-141 004) : Evaluation of Climgen model to generate weather parameters under different climatic situations in Punjab. J Agrometeorol 2008, 10(1), 39-45 .

ClimGen (weather generator) generated data was compared to the observed weather data of Ballowal, Ludhiana and Bathinda weather stations representing different type of climatic situations in Punjab. Several years of daily data of solar radiation, maximum and minimum temperature, morning and evening relative humidity, rainfall and wind speed were used as input and five years data were used for validation purpose. Evaluation was done on the basis of coefficient of determination (R²), Residual Mean Square Error (RMSE), General Standard Deviation (GSD) and Wilmott's index (d) of agreement between generated and observed data. The ClimGen generated data for maximum and minimum temperature showed good performance (GSD d" 0.10 and d e" 0.95) and the data generated for morning relative humidity was acceptable (GSD > 0.10 but d" 0.20 and d < 0.95 but e" 0.90) while evening relative humidity and wind speed were poor except for Ludhiana station. However, the generated rainfall data was poor for all the stations and hence, cannot be accepted. Overall, results indicated ClimGen a good performer as a weather generator for certain parameters.

1 illus, 4 tables, 12 ref

018525   Badarinath K V S;Kharol S K (Atmospheric Science Section, Oceanography Div, , National Remote Sensing Agency, Balanagar, Hyderabad-500 037, Email: badrinath_kvs@nrsa.gov.in) : Aerosol properties during ICARB-2006 campaign period at Hyderabad, India using ground-based measurements and satellite data. J Earth Syst Sci 2008, 117(S1), 413-20.

Continuous and campaign-based aerosol field measurements are essential in understanding fundamental atmospheric aerosol processes and for evaluating their effect on global climate, environment and human life. Synchronous measurements of Aerosol Optical Depth (AOD), BlackCaxboij^BC) aerosol mass concentration and aerosol particle size distribution were carried out during the campaign period at tropical urban regions of Hyderabad, India. Daily satellite datasets of DMSP-OLS were processed for night-time forest fires over the Indian region in order to understand the additional sources (forest fires) of aerosol. The higher values in black carbon aerosol mass concentration and aerosol optical depth correlated well with forest fires occurring over the region. toring Instrument (OMI) aerosol index (AI) variations showed absorbing aerosols over the region ground measurements.

6 illus, 28 ref

018524   Aytek A;Asce M;Alp M (Civil Engineering Dep, Hydraulics Div, Gaziantep Univ, 27310 Gaziantep, Turkey, Email: aytek@gantep.edu.tr) : Application of artificial intelligence for rainfall-runoff modeling. J Earth Syst Sci 2008, 117(2), 145-55.

Study proposes an application of two techniques of artificial intelligence (AI) for rainfall-runoff modeling: the artificial neural networks (ANN) and the evolutionary computation (EC). Two different ANN techniques, the feed forward back propagation (FFBP) and generalized regression neural network (GRNN) methods are compared with one EC method, Gene Expression Programming (GEP) which is a new evolutionary algorithm that evolves computer programs. The daily hydro-meteorological data of three rainfall stations and one streamflow station for Juniata River Basin in Pennsylvania state of USA are taken into consideration in the model development. Statistical parameters such as average, standard deviation, coefficient of variation, skewness, minimum and maximum values, as well as criteria such as mean square error (MSE) and determination coefficient (R²) are used to measure the performance of the models. The results indicate that the proposed genetic programming (GP) formulation performs quite well compared to results obtained by ANNs and is quite practical for use. It is concluded from the results that GEP can be proposed as an alternative to ANN models.

6 illus, 4 tables, 45 ref

018523   Ashwini Kumar;Sudheer A K;Sarin M M (Physical Research Laboratory, , Navrangpura, Ahmedabad-380 009, Email: sarin@prl.res.in) : Chemical characteristics of aerosols in MABL of Bay of Bengal and Arabian sea during spring inter-monsoon: a comparative study. J Earth Syst Sci 2008, 117(S1), 325-32.

The chemical composition of aerosols in the Marine Atmospheric Boundary Layer (MABL) of Bay of Bengal (BoB) and Arabian Sea (AS) has been studied during the spring and inter-monsoon (March-May-May 2006) based on the analysis of water soluble constituents (Na⁺, NH⁺₄, K⁺, Mg²⁺, Ca²⁺, Cl^-, NO^-3₃ and SO^-2), crustal elements (Al, Fe, and Ca) and carbonaceous species (EC, OC). The total suspended particulates (TSP) ranged from 5.2 to 46.6 μg m^-3 and 8.2 to 46.9 μg m^-3 during the sampling transects in the BoB and AS respectively. The water-soluble species, on aver- age, accounted for 44% and 33% of TSP over BoB and AS respectively, with dominant contribution of SO^-2₄ over both the oceanic regions. However, distinct differences with respect to elevated abundances of NH₄⁴ in the MABL of BoB and that of Na⁺ and Ca²⁺ in AS arc clearly evident. The non-sea-salt component of SO^2-₄ ranging from 82 to 98% over BoB and 35 to 98% over AS; together with nss-Ca²⁺/nss-SO₄ equivalent ratios 0.12 to 0.5 and 0.2 to 1.16, respectively, provide evidence for the predominance of anthropogenic constituents and chemical transformation processes occurring within MABL. The concentrations of OC and EC average around 1.9 and 0.4 μg m^-3 in BoB and exhibit a decreasing trend from north to south; however, abundance of these carbonaceous species are not significantly pronounced over AS. The abundance of Al, used as a proxy for mineral aerosols, varied from 0.2 to 1.9 μg m^-3 over BoB and AS, with a distinctly different spatial pattern - decreasing north to south in BoB in contrast to an increasing pattern in the Arabian Sea.

7 illus, 1 table, 32 ref

018522   Aneesh V R;Mohankumar G;Sampath S (Atmospheric Sciences Div, Centre for Earth Science Studies, PB No. 7250, Akkulam, Thiruvananthapuram-695 031, Email: gmk4833@yahoo.com) : Spatial distribution of atmospheric carbon monoxide over Bay of Bengal and Arabian sea: measurements during pre-monsoon period of 2006. J Earth Syst Sci 2008, 117(4), 449-55.

Indian Space Research Organization (ISRO) conducted the 'Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB)' for a two-month pre-monsoon period in 2006 with the ocean segment covering Bay of Bengal and Arabian Sea. During this campaign, carbon monoxide (CO) was continuously monitored using a non-dispersive IR analyser. Quantifying CO in ambient air is vital in determining the air quality of a region. Being toxic. CO is a criteria pollutant, but it is a weak green house gas. Globally, very few measurements exist over marine atmospheres to study its temporal pattern; particularly in situ CO measurements are few over the Bay of Bengal and Arabian Sea for comparison. Present measurements indicate: (i) predominant single peak in the diurnal pattern of CO over the marine atmosphere in contrast to the double peak over the continent, (ii) the mean diurnal CO over the marine atmosphere showing an increasing trend towards evening hours, (iii) the amplitude of the AN peaks over the marine atmosphere was ~ 100 ppbv, while at a remote island site in the Indian Ocean it was ~ 5 ppbv and (iv) high CO values were observed close to continent and the long range transport by wind also caused CO highs.

12 illus, 15 ref

018521   Almas Begum N;Seethalakshmi P;Muthukkumaran K (Civil Engineering Dep, National Institute of Technology, Tiruchirapall, Email: n_almas@rediffmail.com) : Lateral load capacity of single pile located at slope crest. Indian Geotech J 2008, 38(3), 278-94.

Performance of pile foundation subject to lateral load is of considerable importance in geotechnical practices. Many transmission towers, high rise buildings, bridges, coastal and offshore structures are constructed near slopes and are supported by pile foundation. These structures may be subjected to large lateral loads due to winds, waves, currents, earthquakes and lateral soil movement. When piles are constructed in sloping ground, the behaviour of piles under lateral load differs from piles in horizontal ground. The main objective of the present investigation is to study the behaviour of piles on sloping ground under lateral loads. A series of model test had been carried out using instrumented pile embedded in sand of various relative density to study the lateral load deflection behaviour of pile on horizontal ground, 1V: 1.5H and 1V: 2H slopes. The experimental investigations were also extended to study the effect of embedment length to diameter ratio of 25, 30, and 35 under lateral load. Based on the experimental investigation conclusions are drawn for the effect of slope, embedment length to diameter ratio and relative density on lateral load deflection and bending moment behaviour.

16 illus, 5 tables, 12 ref

018520   Alappattu D P;Bala Subrahamanyam D; Kunhikrishnan P K;Somayaji K M;Bhat G S;Venkatesan R;Dutt C B S; Bagavath Singh A;Soni V K;Tripathi A S (Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram-695 022, Email: dennyalp@gmail.com) : Marine atmospheric boundary layer characteristics over Bay of Bengal and arabian sea during the integrated campaign for aerosola, gases and radiation budget (ICARB). J Earth Syst Sci 2008, 117(S1), 281-91.

Detailed measurements were carried out in the Marine Atmospheric Boundary Layer (MABL) during the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) which covered both Arabian Sea and Bay of Bengal during March to May 2006. In this paper, we present the meteorological observations made during this campaign. The latitudinal variation of the surface layer turbulent fluxes is also described in detail.

10 illus, 3 tables, 36 ref

017506   Wenmenga U (UFR/SVT, des Sciences de la Terre Dep, Universite de Oaugadougou 03, 03 BP 7021, Burkina Faso, Email: urbain_wenmenga@univ-ouaga.bf) : Geology, mineralogy and geochemistry of the Kaolin deposits of Ouahigouya area, Burkina Faso, West Africa. J Geol Soc India 2007, 70(6), 1015-20.

Metallogenetic district of Ouahigouya area, north west of Burkina Faso in the West- African craton, contains modest white kaolin deposits, whose exact reserves remain to be evaluated from the point of view of industrial utilization. Of six identified deposits, mineralogy and geochemistry of four were studied by X- ray diffraction methods, scanning electron microscopy, ICP- OES and ICP- AES spectrometry. The identified minerals phases common to all the deposits are by order of importance, kaolinite, quartz, paragonite and illite. Relatively moderate content of silica and alumina, low value of iron oxide, dry shrinkage and white firing colour are suitable features for the use of kaolins in white ceramic field. The kaolin deposits of this area, are genetically related to the hydrothermal and juvenile supergene alteration of Birimian layered felsic pyroclastics.

6 illus, 2 tables, 12 ref

017505   Venkateshwarlu M;Ojha J R;Pandey B;Krishna J (Palaeomagnetism Div, National Geophysical Research Institute, Hyderabad-500 606, Email: mamila_v@rediffmail.com) : Preliminary remanent magnetism rsults from the Jurassic sediments of Kachchh, India. Curr Sci 2008, 95(6), 725-7.

^ssc3 illus, 2 tables, 14 ref

017504   Tiwari R N;Mishra D (Geology Dep, Banaras Hindu University, Varanasi-221 005, Email: rntiwar@yahoo.com ) : Microfacies analysis of transgressive condensed sequence: a study from the Oxfordian of Kachchh Basin, Gujarat. J Geol Soc India 2007, 70(6), 923-32 .

Study of microfacies suggests that the deposition of the Dhosa Oolite Member took place in an open marine shallow shelf environment with clear proximal-to-distal trend from southeast to northwest. Two transgressive pulses were responsible for its formation. An earlier slow and frequently interrupted transgression together with subsidence is recorded by abrupt change in clastic grain size, mixing of two lithologies and abundance of siliciclastics in each microfacies. Later, rapid transgression is suggested by the extremely reduced thickness, erosive to irregular contacts, development of intraformational conglomerates, multiphase reworked sediments, an increase in the abundance of carbonates and ammonites and negligible sediment input. Lateral variation in the microfacies and their assemblages together with variable extent of marine mega fauna (ammonites) from southeast to northwest marks the depositional slope of the basin towards northwest during studied interval. The mixed lithologies in this condensed sequence together with the bioturbated nature of sediments suggest that the rate of sedimentation was extremely slow.

4 illus, 4 tables, 19 ref

017503   Tiwari G S (Petrology Div, Geological Survey of India, Lucknow-226 024, Email: gstgsi@rediffmail.com) : Variation of heavy minerals in different lithofacies and geomorphic units of the Ganga - Yamuna river near their confluence at Allahabad, Uttar Pradesh. J Geol Soc India 2008, 71(1), 133-9.

Recent sediments of the Ganga and Yamuna Rivers in three sectors, viz. Sector-A, Sector-B and Sector-C were subjected for heavy minerals study to understand their distribution in various fades, and differences and similarities. The heavy minerals include garnet, hornblende, kyanite, tourmaline, epidote, sillimanite, zircon, chloritoid, apatite and staurolite. There exists an inverse relationship between their percentage and grain size. Among the heavies, garnet dominates in all the three sectors of study area, followed by hornblende in Sector-A and -B, and epidote in Sector-C with augite and rutile in the Sector-B only. Anatase, hypersthene, sphene and corundum are restricted to Yamuna river sediments. Also, brookite is more common in Sector-A. Nine lithofacies, namely St, Sp₂, Sp₁, Sr₁, Sr₂, Sl, Sh, Fl and Fm (8 Sand-and l Mud-sublithofacies) are identified in the area. Irrespective of occurrence in any geomorphic unit, Sr₁ - Sr₂ facies have higher concentration of heavies in coarser fraction while the Sp₁ - Sp₂ facies have higher concentration of heavies in finer fraction. Bed forms have significant control on the distribution of the heavy minerals in a vertical profile, with differences in the source of the sediments of the Ganga and Yamuna Rivers reflected well in the respective heavy mineral assemblage.

2 illus, 2 tables, 12 ref

017502   Suneetha P;Ramarao Y V;Bhanu Kumar O S R U (Meteorology & Oceanography Dep, Andhra Univ, Visakhapatnam-530 003) : Forecasting of tropical cyclone using QLM model over the Arabian sea. J Agrometeorol 2008, 10(Spl-Pt II), 349-52.

Main aim of this study is to predict the central pressure, vorticiiy, winds, around the eye of tropical cyclone and its track during 5-10 May 2004 over the Arabian Sea using Quasi lagrangian model (QLM), The main synoptic feature of it is that it caused exceptionally heavy rainfall of 117cm at Aminidivi (11.1°N/72.7°E) during the 24 hr period ending 0300UTC of 6 May. The GLM model has predicted a mean sea level pressure of 994 hPa and vorticity near the center based on the initial conditions of 6 May/OOUTC and wind at 850hPa brings out a well developed cyclonic circulation with wind speeds of 40-50 knots. The model forecast indicates that the predicted storm track is very close to the observed track; it has produced the initial structure of the storm and maintained the intensity of the system. Next, forecast verification has been carried out for the geographical distance between the predicted location of the storm and the verifying position at valid hour. The QLM results highlight that the mean error of 24hrs forecast is about 146km, which increases to about 248km for 48hr forecast and 172km for 72ht forecast. Finally simulated central pressure, vorticity and winds are validated with the datasets of India Meteorological Department and satellite products and the results are promising.

5 illus, 1 table, 6 ref

017501   Sridhar S G D;Hussain S M;Periakali P;Kumar V (Applied Geology Dep, School of Earth and Atmospheric Sciences, University of Madras, Guinddy Campus, Chennai-600 025, Email: sg_sri@yahoo.co.in) : Ostracod Kotoracythere inconspicua (Brady) from the Palk Bay, off Rameswaram, southeast coast of India. J Geol Soc India 2007, 70(6), 981-6.

Shallow marine and tropical ostracod taxon Kotoracythere inconspicua (Brady) is encountered from the surface sediments of Indian waters. Fifty-two sediment and bottom water samples were collected over an year, representing the four seasons, in a transect (depth 0 - 13 m) off Rameswaram, southeast coast of India. Living specimens of this species are found in all the seasons. Systematics and ecology of the species are presented. Biogeographically, this taxon has an extremely wide distribution in tropical, littoral zones of all oceans, excepting east Pacific. Its wide geographic distribution is explained through currents and by passive dispersal by ships.

3 illus, 1 table, 28 ref